1. Field
The present disclosure relates generally to communication systems, and more particularly, to peer discovery interference management in a wireless wide area network (WWAN).
2. Background
In a WWAN, all communication between mobiles goes through uplink/downlink channels between wireless devices and the base station. Two communicating wireless devices that are in the vicinity of each other may communicate directly without going through the base station. Such direct peer-to-peer communication can enable new types of services and/or reduce the traffic load on the base station.
To enable peer-to-peer communication, wireless devices in the vicinity of each other must be able to discover each other. Wireless devices may discover each other by periodically transmitting peer discovery signals. The presence of a wireless device may be detected by receiving and decoding the peer discovery signal from that wireless device. A WWAN base station may set aside time frequency resources for wireless devices to transmit their peer discovery signals. The allocated time frequency resources may be concurrent with downlink and/or uplink WWAN resources.
In order to maximize the range of peer discovery, wireless devices may transmit their peer discovery signals at a maximum power. Transmission of peer discovery signals at maximum power can cause interference to WWAN (or other non peer discovery) communication in neighboring cells which are scheduled on the same time/frequency resource. This scenario can arise when an adjacent base station sets aside different resources for peer discovery and/or when the serving base station and an adjacent base station are not fully synchronized. The interference to WWAN communication may be reduced by reducing a transmission power. However, reducing the transmission power decreases the range of peer discovery and/or increases the latency of peer discovery. As such, techniques are needed for reducing interference to WWAN communication due to the transmission of peer discovery signals that have less impact on the range/latency of peer discovery.